1. Field of the Invention
The present invention relates to an improvement on a wheel structure, more particularly one, which is relatively easy to assemble; the wheel structure includes an upper cover having a connecting extension section for allowing a braking mechanism to pivot on.
2. Brief Description of the Prior Art
Hospital beds are usually equipped with wheels so that they can serve substantially the same purpose as wheelchairs to transfer patients rapidly and easily from sick chambers to other divisions of a hospital such as an examination division.
Hospital beds and wheelchairs are further equipped with a brake mechanism for stopping/immobilizing the wheels.
A kind of wheel for use with hospital beds/wheelchairs includes a wheel supporting member, a shaft, a wheel member pivoting on the wheel supporting member, a bearing fitted on the wheel support member, a toothed disk arranged under the bearing, and a straightforward motion limiting device, a braking device.
The wheel supporting member has protruding ear portions on two sides thereof. The straightforward motion limiting device includes a straightforward motion limiting board facing the toothed disk, a straightforward motion limiting pedal, and a releasing board pivoted on the protruding ear portions of the wheel supporting member. The braking device includes a brake motion limiting board, and a brake pedal, which is pivoted on the protruding ear portions of the wheel supporting member like the releasing board of the straightforward motion limiting device.
The toothed disk has a straightforward motion limiting cavity, and a brake motion limiting cavity. The straightforward motion limiting board has at a front portion thereof an upward limiting protrusion to pass into the straightforward motion limiting cavity of the toothed disk. Furthermore, the brake motion limiting board has at a front portion thereof several upward protrusions to pass into the brake motion limiting cavity of the toothed disk.
The above wheel has the following drawbacks: It is difficult and takes much time to pivot the brake pedal of the braking device to the protruding ear portions of the wheel supporting member because there is only a small space between the protruding ear portions and the body of the wheel supporting member. And, the brake pedal is prone to shake. Third, the manufacturing cost of the wheel supporting member is relatively high owing to the existence of the protruding ear portions. Because the bearing is only held in position by means of a bearing holder and a fixing sleeve, which is pressed against a top of the bearing holder, it will tilt easily when the shaft is swaying left and right; consequently, the bearing can get damaged after it is used for a certain length of time.